1. Field of the Invention
The present invention relates to a method of local dimming of a light source, a light source apparatus for performing the method, and a display apparatus having the light source apparatus. More particularly, the present invention relates to a method of local dimming of a light source which includes driving the light source, which includes a plurality of light-emitting blocks, by individually driving light-emitting blocks of the plurality of light-emitting blocks, a light source apparatus for performing the method, and a display apparatus having the light source apparatus.
2. Description of the Related Art
Generally, a liquid crystal display (“LCD”) apparatus includes an LCD panel which displays an image by varying an optical transmittance of liquid crystal molecules disposed in the LCD panel. A backlight assembly is typically disposed below the LCD panel to provide the LCD panel with light.
The LCD panel typically includes an array substrate, a color filter substrate and a liquid crystal layer disposed therebetween. The array substrate typically includes a plurality of pixel electrodes and a plurality of thin-film transistors (“TFTs”). TFTs of the plurality of TFTS are electrically connected to pixel electrodes of the plurality of pixel electrodes. The color filter substrate is disposed opposite to, e.g., facing, the array substrate and has a common electrode and a plurality of color filters disposed thereon. The liquid crystal layer includes the liquid crystal molecules and is interposed between the array substrate and the color filter substrate.
When an electric field, generated between the pixel electrodes and the common electrode, is applied to the liquid crystal layer, an arrangement of the liquid crystal molecules of the liquid crystal layer is altered to change an optical transmissivity thereof. As a result, a desired image is displayed. Typically, the LCD panel displays a white image having a high luminance when an optical transmittance is maximum, and the LCD panel displays a black image having a low luminance when the optical transmittance is minimum.
However, the liquid crystal layer is difficult to arrange in a uniform direction, and light leakage is thereby generated when the LCD panel displays an image corresponding to a low gradation, for example. Specifically, it is difficult for the LCD panel to display a fully black image at a low gradation, and a contrast ratio (“CR”) of the image displayed on the LCD panel is thereby degraded, e.g., decreases.
To prevent the contrast ratio of the image from decreasing, a method of local dimming of a light source has been developed. In the method, a light source is driven to individually control amounts of light according to a position in the LCD panel. In the method of local dimming of the light source, the light source is typically divided into a plurality of light-emitting blocks to control the amounts of light of each of the light-emitting blocks of the plurality of light-emitting blocks based on locations of relatively dark and light areas in a display area of the LCD panel. For example, a light-emitting block corresponding to a display area displaying a black image is driven at a low luminance (e.g., is turned off), while a light-emitting block corresponding to a display area displaying a white image is driven at a high luminance.
However, even though the light source is driven by light-emitting blocks according to an image displayed on the LCD panel, display defects, such as light leakage and flicker, for example, are generated. For example, when a given light-emitting block is lighted and peripheral light-emitting blocks disposed around a periphery of the given light-emitting block are not lighted, light leakage is generated in the LCD panel near the given light-emitting block, and a fully black image is not displayed. Moreover, when the LCD panel displays a moving image, positions of lighted light-emitting blocks rapidly move, and flicker is generated in the LCD panel.